The essential components of a conventional chocolate formulation are cocoa "nib" (i.e., the roasted cocoa bean with shell and germ removed), sugar, and cocoa butter in addition to the cocoa butter contained in the nib. Cocoa nib is approximately 50% cocoa butter, the balance being proteins, carbohydrates, tannins, acids, and the like. The cocoa butter content of the chocolate controls its setting characteristics and largely governs its cost. While the ratio of cocoa nib to sugar determines the type of chocolate, the cocoa butter content varies according to the application. Thus, bitter sweet chocolate has a nib to sugar ratio of about 2 to 1 while sweet chocolate has a ratio of about 1 to 2. Molding chocolate may have a fat content of about 25% to 40%, covering chocolate about 33 to 36%, chocolate for hollow goods about 38 to 40%, and chocolate for covering ice cream about 50 to 60%.
The typical preparation of chocolate involves four general operations or steps. In the first operator, the ingredients are mixed together in a process which also involves grinding or rubbing (e.g., on a multiple roll press) to provide a smooth fluid paste of uniform and specific particle size. The ingredients may be added sequentially and/or, in particular the cocoa butter, may be added stepwise to help control the viscosity of the composition. The sugar may also be preground to a smaller particle size to reduce the length of time required in the grinding/rubbing (i.e., refining) of the chocolate mixture. Most chocolate, and certainly all good quality chocolate, is subjected after refining or mixing to the process of "conching" in which the chocolate mixture is subjected to temperature treatment and mechanical working to give the chocolate an improved texture and a fuller and more homogeneous flavor. Other ingredients such as flavors (e.g., vanilla and extra cocoa butter) may be added during this operation, if desired. A frequently added additional ingredient is lecithin or other emulsifiers which improves the flow properties of the chocolate and thereby enables the amount of fat to be reduced. The third operation of the chocolate preparation is called "tempering" in which nuclei are provided in the liquid chocolate composition to facilitate the rapid crystallization of selected stable fat crystals on cooling. The final appearance of the chocolate, its texture and keeping properties depend upon correct tempering conditions. After tempering, the chocolate may finally be cast into molds to set or may be used in an enrobing process to produce the desired chocolate products.
The present invention is concerned in particular with the first operation (i.e., the refining step) of the chocolate-making process. The refining step or process is often the limiting or bottleneck portion of the entire chocolate-making process. Generally, the refining step is carried out using one or more three- or five-roll presses to obtain a smooth fluid paste of uniform and specific particle size (generally about 15 to 50 microns in diameter with a relatively narrowly particle size distribution). Attempts to speed up the refining process, while still maintaining the desired particle size profile, have generally been unsuccessful. In most cases, simply speeding up the process does not allow the desired particle size profile to be maintained and will result in a larger than desired average particle size material going into the conching process and in the final product.
It would be desirable, therefore, to provide a method for increasing the flowrate in the refining process without significantly increasing the average particle size or particle size distribution of the refined chocolate mass. It would also be desirable to provide such a method which could be utilized on existing multiple roll press chocolate refining equipment. It would also be desirable to provide such a method which could be even more effectively utilized on newly designed chocolate refining equipment. The methods of the present invention are able to provide such advantages to both existing and newly designed chocolate-making processes.